Glossary
AFUE
Annual Fuel Utilization Efficiency is a measure of a gas furnace’s efficiency in converting fuel to energy – the higher the rating, the more efficient the unit. For example: a rating of 90 means that approximately 90 percent of the fuel is used to provide warmth to your home while the remaining 10 percent escapes as exhaust. Another way to look at it is that a 90% efficient furnace uses 90 cents of each energy dollar to heat your home while 10 cents literally goes up the flue.
BTU
British Thermal Unit is the amount of heat it takes to raise one pound of water one degree Fahrenheit. For your home, it represents the measure of heat given off when fuel is burned for heating or the measure of heat extracted from your home for cooling.
CFM
Cubic Feet Per Minute. A standard measurement of airflow. A typical system requires 400 CFM per ton of air conditioning.
Capacity
The output or producing ability of a piece of cooling or heating equipment. Cooling and heating capacities are referred to in BTUs.
Compressor
The heart of an air conditioner or heat pump unit. It is the part of the outdoor unit and pumps refrigerant in order to meet the cooling requirements of the system.
Condenser Coil/Outdoor Coil
In an air conditioner, the coil dissipates heat from the refrigerant, changing the refrigerant from vapor to liquid. In a heat pump system, it absorbs heat from the outdoors.
Damper
Found in ductwork, this movable plate opens and closes to control airflow. Dampers can be used to balance airflow in a duct system. They are also used in zoning to regulate airflow to certain rooms.
Ductwork
Pipes or channels that carry air throughout your home. In a home comfort system, ductwork is critical to performance – in fact, it is as critical as the equipment. Ductwork that is going into an attic or crawl space should be insulated. Supply ducts with heat pumps should be insulated. Ductwork is often undersized. This compromises airflow which, in turn, compromises your comfort. We build much of our ductwork in-house, which is not common. We do this to ensure correct size and duct transitions as well as to make the ductwork look attractive. We fabricate “old school” by hand.
Evaporator Coil/Indoor Coil/A Coils
The other half of your air conditioning system, located inside your home in the indoor unit. This is where the refrigerant evaporates as it absorbs heat from the air that passes over the coil. The heat pump absorbs heat from outside for cooling and the process is reversed in heating mode. It is important for this coil to be matched to the system – not a generic non-matched brand – and to be correctly sized to the system.
Gas Furnace Heat Exchanger
Located in the furnace, the heat exchanger transfers heat to the surrounding air, which is then pumped throughout your home. This is the part that can crack and allow carbon monoxide to enter your home. It is important to have your furnace professionally serviced annually and to change your filters often to help identify/prevent heat exchanger cracks.
HSPF
Heating Seasonal Performance Factor is the rating used in measuring the heating efficiency of a heat pump – the higher the number, the more efficient the unit.
Package Unit
A heating and cooling system contained in one outdoor unit. A package unit is typically installed beside, on the roof of, or sometimes in the attic of a home or business. Package units are not common in residential applications in the greater Kansas City area but are common for light commercial application.
Refrigerant
A chemical that produces a refrigerating effect while expanding and vaporizing. The two most common types of refrigerant are R-22 and R-410A. Refrigerant is regulated by the EPA so make sure anyone dealing with your AC or heat pump is appropriately certified. R-22 is being phased out to protect the ozone. No new equipment will be manufactured with R-22 after 2010 and the manufacturing of R-22 has been phased out completely (as of 2020). We strongly recommend you consider purchasing an R-410A system if you are purchasing a new system. From a practical standpoint, as R-22 is phased out, it will become more and more expensive.
SEER
Seasonal Energy Efficiency Ratio. A measure of cooling efficiency for air conditioners and heat pumps. The higher the “SEER,” the more energy efficient the unit. The government’s minimum SEER rating is currently 13. For comparison, think of it as you would miles per gallon in an automobile.
Split System
The combination of an outdoor unit (air conditioner or heat pump) with an indoor unit (furnace or air handler). Split systems must be matched for optimum efficiency. Split systems are the most common type of system in our geographic area.
Thermostat
Also called a comfort control, a thermostat consists of a series of sensors and relays that monitor and control the functions of a heating and cooling system. The thermostat is like the brain of your heating and cooling system. Thermostats have become amazingly “intelligent” and user-friendly over the last few years. Programmable features and sensors that gauge humidity, need for more heat during start up, etc. are now available. Large digit thermostats are available for the elderly and visually impaired.
Ton
A unit of measurement used for determining cooling capacity. One ton is the equivalent of 12,000 BTUs per hour. Units in new housing are often undersized (as is the ductwork that goes with them) to save the contractor money. A rough rule of thumb is one ton of cooling for each 400 – 600 square feet. This can be heavily impacted by the amount of insulation in the home, the direction the home faces and the number of windows in the house. A heat load is one way to more accurately assess the number of tonnage needed to correctly cool your home for maximum comfort.
Zoning
A method of dividing a home into different comfort zones so each zone can be independently controlled depending on individual use and need. Zoning is a great application for two story homes or homes that have noticeable uneven heating and/or cooling in different areas of the home.